Apparatus for applying multi-component liquid liner compositions to the inner surfaces of conduits and methods of applying same

ABSTRACT

The invention is directed to an apparatus, or system, for applying a multi-component liquid liner composition to an inner surface of a conduit. The system comprises a first reservoir having a first liquid liner component; a second reservoir having a second liquid liner component, the second liquid liner component being different from the first liquid liner component; a first liquid liner component transmission line in communication with the first reservoir; a second liquid liner component transmission line in communication with the second reservoir; and an applicator in communication with the first and second liquid liner component transmission lines. Methods of applying multi-component liquid liner compositions to the inner surface of conduits are also disclosed.

BACKGROUND OF THE INVENTION

[0001] 1. Field Of The Invention

[0002] This invention relates to an apparatus, or system, for applying amulti-component liquid liner composition to the inner surface of aconduit, and in particular, well bore tubing, while the conduit remainsin place. The invention also relates to methods for applying amulti-component liquid liner composition to the inner surface ofconduits.

[0003] 2. Description of Related Art

[0004] During the past several years, the oil and gas industry has beenchallenged to find new ways for improving operating efficiencies whilemeeting the ever increasing demand for oil and gas. With overallproduction output dropping below consumption levels, it has becomeincreasingly important for producers to maximize their currentproduction. This requires that they minimize any downtime when a wellmust be pulled out of service for workover operations.

[0005] One of the most costly workover operations is the pulling andreplacement of the production tubulars, i.e., well bore tubing(“tubing”) or casing. These conduits are a primary means for pressurecontainment and oil and gas transfer during production. If theproduction tubulars fail, a loss of well control may result with thefurther possibility of an uncontrolled release of gas and oil from thewell.

[0006] Many of the wells that are currently producing have developedwall thickness reductions in the well bore tubing that may eventuallylead to a leak or failure. Wall thickness reductions usually occur dueto corrosion and erosion over a period of time. Corrosion occurs whenfluids, such as salt water or other corrosive fluids, are producedduring normal oil and gas production. Certain fluids and gaseschemically attack the metal of the well bore tubing causing general lossof wall thickness and localized pitting of the well bore tubing untilthe wall is eventually breached. Erosion causes wall thickness lossesdue to the physical contact and the gouging action of abrasiveparticles, such as sand, carried by the produced fluids.

[0007] One way to prevent corrosion and reduce erosion is to installtubing that has an internal protective coating. These coatings canreduce wall loss, greatly extending the life of the tubing and reducingthe need for workover operations. However, internally coated tubing isvery expensive and requires that the existing tubing be pulled and newtubing installed.

[0008] In another approach, a continuous length of solid liningmaterial, e.g., plastic or polyethylene pipe, is inserted into thetubing of the well. The solid lining material is pulled into the conduitor inserted through an outside-diameter-reduction unit and held intension with weight or other means until the solid lining material issufficiently deformed to permit installation of the solid liningmaterial into the conduit. The solid lining material is then positionedat, e.g., lowered to, the desired location in the conduit, e.g., at azone located at a specific depth, e.g., 1,000 feet. The tension is thenreleased and the solid lining material is allowed to relax and expand,or lay loosely, against the inner surface of the conduit.

[0009] This lining method has many disadvantages. For example, itrequires expensive equipment that is not always available. Additionally,in some instances, sections of the plastic liner must be removed frominside of the conduit to allow valves and other assemblies in theconduit to function correctly. Moreover, this method is time consumingand problematic to perform due to varying dimensions and configurationsof the valves and other assemblies in the production tubing. As such,this method generally requires special tools to be designed, fabricated,and operated for removing the plastic liner from the inside of each ofthese assemblies. This process also requires the use and transportationof large, specialized equipment for each operation. As mentioned above,the equipment is not readily available in many areas and it iscontemplated that the equipment, when available, may not permit safeoperations on pressure-containing conduits.

[0010] Another approach involves a method that requires placement orinjection of a liquid coating between two pigs, or wiper plugs, andmoving the wiper plugs at a pre-determined rate along the inner surfaceof the conduit over a desired distance. Liquid coating is locatedbetween the wiper plugs and is applied to the inner surface of theconduit between the wiper plugs as the wiper plugs move along the innersurface. This process is referred to as an “in-situ” coating because itpermits the conduit to remain in place, or in its operational location,while the coating is applied.

[0011] While in-situ coating is used in various pipeline applications,it has not been successfully used in production tubular applications ormany other applications due to various shortcomings. For example,in-situ coating methods require the use of a liquid coating materialthat will stay in a liquid state for extended periods of time to avoidcuring, or hardening, between the wiper plugs while the plugs move alongthe inner surface of the conduit. Additionally, the use of wiper plugsrequires two openings in the conduit. The first opening is the insertionpoint and the second opening is the exit point. Therefore, the wiperplugs move along the inner surface from the insertion point to the exitpoint.

[0012] Generally, the liquid coating material in this method is either asingle component liquid, or a multi-component liquid that is mixed priorto transmitting the liquid to the application site, i.e., the locationalong the inner surface of the conduit desired to be coated by theliquid coating material. In these prior attempts, the liquid curesprematurely and prevents the successful coating of the inner surface ofthe tubing. For example, extended time periods for transmission of theliquid coating material through the conduit and elevated temperatures atthe application site have been determined to cause these liquid coatingmaterials to cure prematurely.

[0013] Additionally, because the conditions, e.g., temperature,pressure, humidity, etc., may vary at different application sites alongthe inner surface of the conduit, the premixed liquid cannot becustomized for the varying conditions at the application sites. Thislack of flexibility has resulted in liquid coating compositions thateither cure too quickly, or, in many cases, not at all.

[0014] Additionally, this practice does not allow the chemical(s) orliquid component(s) to be tailored during the process and may not beused when the conduit is limited to a single opening. Therefore, in manyinstances, the inner surface of the tubing is not adequately coated bythe single or multi-component liquid coating compositions currentlyemployed.

[0015] Accordingly, prior to the development of the present invention,there has been no system for applying a multi-component liquid linercomposition to the inner surface of a conduit and method of applying amulti-component liquid liner composition to the inner surface of aconduit, which: permits in-situ coating of production tubulars withouthaving the liquid coating composition cure prematurely; permits coatingof the inner surface of the production tubulars without having toextract old tubing and replace with new tubing; permits the applicationsite to be more easily targeted around valves and other assemblies;decreases the amount of time production of oil and gas is interrupted;permits independent, or isolated, transmission of liquid linercomponents to the application site; and is less expensive than tubingreplacement using new conventional tubing or tubing that is pre-coatedprior to installation in the well. Therefore, the art has sought asystem for applying a multi-component liquid liner composition to theinner surface of a conduit and method of applying a multi-componentliquid liner composition to the inner surface of a conduit which:permits in-situ coating of production tubulars without having the liquidcoating composition cure prematurely; permits coating of the innersurface of the production tubulars without having to extract old tubingand replace with new tubing; permits the application site to be moreeasily targeted around valves and other assemblies; decreases the amountof time production of oil and gas is interrupted; permits independent,or isolated, transmission of liquid liner components to the applicationsite; and is less expensive than tubing replacement using new tubing ortubing that is pre-coated prior to installation in the well.

SUMMARY OF INVENTION

[0016] In accordance with the invention the foregoing advantages havebeen achieved through the present system for applying a multi-componentliquid liner composition to an inner surface of a conduit comprising: afirst reservoir having a first liquid liner component; a secondreservoir having a second liquid liner component, the second liquidliner component being different from the first liquid liner component; afirst liquid liner component transmission line in communication with thefirst reservoir; a second liquid liner component transmission line incommunication with the second reservoir; and an applicator incommunication with the first liquid liner component transmission lineand the second liquid liner component transmission line.

[0017] A further feature of the system for applying a multi-componentliquid liner composition to an inner surface of a conduit is that thefirst and second reservoirs and first and second liquid liner componenttransmission lines may be in communication with a multi-port pump.Another feature of the system for applying a multi-component liquidliner composition to an inner surface of a conduit is that the first andsecond liquid liner component transmission lines may be adjacent eachother to form a control line. An additional feature of the system forapplying a multi-component liquid liner composition to an inner surfaceof a conduit is that the control line may include a power source line.Still another feature of the system for applying a multi-componentliquid liner composition to an inner surface of a conduit is that thepower source line may be electric. A further feature of the system forapplying a multi-component liquid liner composition to an inner surfaceof a conduit is that the power source line may be pneumatic. Anotherfeature of the system for applying a multi-component liquid linercomposition to an inner surface of a conduit is that the control linemay be coiled. An additional feature of the system for applying amulti-component liquid liner composition to an inner surface of aconduit is that the control line may be maintained on a reel. Stillanother feature of the system for applying a multi-component liquidliner composition to an inner surface of a conduit is that theapplicator may be a directional spray nozzle. A further feature of thesystem for applying a multi-component liquid liner composition to aninner surface of a conduit is that the applicator may be a centrifugalspray nozzle. Another feature of the system for applying amulti-component liquid liner composition to an inner surface of aconduit is that the first and second liquid liner component transmissionlines may be coiled.

[0018] In accordance with the invention the foregoing advantages havealso been achieved through the present method of applying amulti-component liquid liner composition to an inner surface of aconduit, comprising the steps of: providing a conduit having an innersurface; transmitting a first liquid liner component to an applicationsite disposed on the inner surface of the conduit; transmitting a secondliquid liner component to the application site, the second liquid linercomponent being different from the first liquid liner component; mixingthe first liquid liner component with the second liquid liner componentat the application site to form a multi-component liquid linercomposition; and applying the multi-component liquid liner compositionto the inner surface of the conduit at the application site.

[0019] A further feature of the method of applying a multi-componentliquid liner composition to an inner surface of a conduit is that athird liquid component liner component may be transmitted to theapplication site and mixed with the first and second liquid linercomponents to form the multi-component liquid liner composition appliedto the inner surface of the conduit at the application site. Anotherfeature of the method of applying a multi-component liquid linercomposition to an inner surface of a conduit is that the multi-componentliquid liner composition may include at least two additional liquidliner components that are transmitted to the application site and mixedwith the first and second liquid liner components to form themulti-component liquid liner composition applied to the inner surface ofthe conduit at the application site. An additional feature of the methodof applying a multi-component liquid liner composition to an innersurface of a conduit is that the conduit may be production tubulars andthe application site may be disposed at least 200 feet below ground.Still another feature of the method of applying a multi-component liquidliner composition to an inner surface of a conduit is that themulti-component liquid liner composition may be applied to the innersurface of the conduit by centrifugal spraying.

[0020] In accordance with the invention the foregoing advantages havealso been achieved through the present method of applying amulti-component liquid liner composition to an inner surface of aconduit, comprising the steps of: providing a conduit having an innersurface; transmitting a first liquid liner component to an applicationsite disposed on the inner surface of the conduit; transmitting a secondliquid liner component to the application site, the second liquid linercomponent being different from the first liquid liner component;applying the first liquid liner component to the inner surface of theconduit at the application site; and applying the second liquid linercomponent to the inner surface of the conduit at the application sitethereby forming a multi-component liquid liner composition disposed onthe inner surface of the conduit at the application site.

[0021] A further feature of the method of applying a multi-componentliquid liner composition to an inner surface of a conduit is that atleast one additional liquid liner component may be transmitted to theapplication site and applied to the inner surface of the conduit to formthe multi-component liquid liner composition disposed on the innersurface of the conduit at the application site. Another feature of themethod of applying a multi-component liquid liner composition to aninner surface of a conduit is that the conduit may be productiontubulars and the application site may be disposed at least 200 feetbelow. An additional feature of the method of applying a multi-componentliquid liner composition to an inner surface of a conduit is that thefirst and second liquid liner components may be applied to the innersurface of the conduit by centrifugal spraying.

[0022] The apparatus for applying multi-component liquid linercompositions to the inner surfaces of conduits and methods of applyingmulti-component liquid liner compositions to the inner surfaces ofconduits have the advantages of: permitting in-situ coating ofproduction tubulars without having the liquid coating composition cureprematurely; permitting coating of the inner surface of the productiontubulars without having to extract old tubing and replace with newtubing; permitting the application site to be more easily targetedaround valves and other assemblies; decreasing the amount of timeproduction of oil and gas is interrupted; permitting independent, orisolated, transmission of liquid liner components to the applicationsite; and being less expensive than tubing replacement using new tubingor tubing that is pre-coated prior to installation in the well.

BRIEF DESCRIPTION OF DRAWINGS

[0023]FIG. 1 is side view of one specific embodiment of the system forapplying a multi-component liquid liner composition to the inner surfaceof a conduit.

[0024]FIG. 2 is a side view of the conduit and the applicator of thesystem for applying a multi-component liquid liner composition shown inFIG. 1.

[0025]FIG. 3 is a cross-sectional view of the control line of anotherspecific embodiment of the system for applying a multi-component liquidliner composition.

[0026] While the invention will be described in connection with thepreferred embodiment, it will be understood that it is not intended tolimit the invention to that embodiment. On the contrary, it is intendedto cover all alternatives, modifications, and equivalents, as may beincluded within the spirit and scope of the invention as defined by theappended claims.

DETAILED DESCRIPTION OF THE INVENTION

[0027] The invention is directed to an apparatus, or system, forapplying a multi-component liquid liner composition to an inner surfaceof a conduit. Multi-component liquid liner compositions are generallypreferred, or required, under certain application conditions, including,but not limited, to high temperatures. If mixed before transmission, ordelivery, to the application site, high temperatures inside the conduitcan cause an accelerated reaction and curing of multi-component liquidliner compositions before they can be applied to the inner surface ofthe conduit. Therefore, one aspect of the present invention is directedto a system that isolates the individual liquid liner components of themulti-component liquid liner composition until just prior to themulti-component liquid liner composition being applied to the innersurface of the conduit.

[0028] It is contemplated that isolation of liquid liner components mayprovide additional benefits in applications where intermittentoperations are being performed. Isolation of the liquid liner componentscan avoid premature reaction and hardening of the multi-component liquidliner composition while the pump is disengaged for prolonged periods oftime. Additionally, isolation of the liquid liner components withmultiple transmission lines permits changes in the multi-componentliquid liner composition during the course of the application of themulti-component liquid liner composition to the inner surface of theconduit, thereby allowing the multi-component liquid liner compositionto be tailored to the specific application, and/or conditions at theapplication site. Moreover, isolating individual liquid liner componentsallows for base components and catalysts or accelerators to be used asliquid liner components and mixed in a more controlled manner at thepoint of application, thereby avoiding premature curing or thickening ofthe multi-component liquid liner composition during application of themulti-component liquid liner composition to the inner surface of theconduit.

[0029] Referring now to FIGS. 1-3, broadly, the system 20 includes firstreservoir 30, first liquid liner component transmission line 31 incommunication with first reservoir 30, second reservoir 40, secondliquid liner component transmission line 41 in communication with secondreservoir 40, third reservoir 50, and third liquid liner componenttransmission line 51 in communication with third reservoir 50. Firstreservoir 30 includes first liquid liner component 35, second reservoirincludes second liquid liner component 45, and third reservoir includesthird liquid liner component 55. Generally, first liquid liner component35, second liquid liner component 45, and third liquid liner component55 are different chemicals that when mixed or combined cure, or harden,to form a solid compound or coating, i.e., the multi-component liquidliner composition 93, such as a resin, thereby forming a liner, orcoating, at application site 95 along inner surface 82 of conduit 80.

[0030] It is to be understood that first liquid liner component 35,second liquid liner component 45, and third liquid liner component 55all do not have to be different from each other provided at least two ofthe liquid liner components are different from each other. First liquidliner component 35, second liquid liner component 45, and third liquidliner component 55 are readily known to persons skilled in art.Additionally, persons of ordinary skill in the art can easily formulatemulti-component liquid liner compositions 93 as desired or necessary dueto conditions at the application site 95 to facilitate effective coatingof inner surface 82 of conduit 80. In one preferred embodiment, firstliquid liner component 35 is a base material, or epoxy resin such asSovachem Tank Liner 8-Series 2 Pack Chemical Resistant Epoxy Tank Liningsold and distributed by Jotun Paints, Inc. of Norway with distributorsin Houston, Tex. and second liquid liner component 45 is a catalyst orharder such as 8T1 catalyst sold by Jotun Paints, Inc. First liquidliner component 35 and second liquid liner component 45 are preferablypresent in a ratio of 6 to 1 based upon volume. In this embodiment,third liquid liner component 55 is not required. Additionally, themulti-component liquid liner composition 93 formed in this embodimentprovides both corrosion and wear resistance at temperatures up to 350°F.

[0031] The speed at which the multi-component liquid liner composition93 solidifies is dependent upon numerous conditions, such as thehumidity, the temperature, the pressure, etc. at application site 95.Because many of these conditions vary from application site toapplication site along the inner surface, system 20 keeps first liquidliner component 35 separate from second liquid liner component 45 andthird liquid liner component 55 until just seconds before themulti-component liquid liner composition 93 is to be applied to innersurface 82 of conduit 80. Therefore, a multi-component liquid linercomposition 93 can be tailored to the conditions at the application site95.

[0032] As shown in FIGS. 1-3, first liquid liner component transmissionline 31, second liquid liner component transmission line 41, and thirdliquid liner component transmission line 51 are preferably adjacent toeach other to form integrated line, or control line, 60. In thisarrangement liquid liner component transmission lines 31, 41, 51 aremaintained in one line and may be easily managed by the operator of thesystem 20.

[0033] In a preferred embodiment, liquid liner component transmissionlines 31, 41, 51 are braided, or twisted or coiled, with each other toform control line 60. In another preferred embodiment, control line 60includes an outer jacket or sheath 49 (FIG. 3) that protects controlline 60 from damage and provides the control line 60 a uniform circularcross-section, or tubular shape. Additionally, control line 60 ispreferably coiled, thereby permitting control line 60 to be disposed ona reel 70. Therefore, because control line 60 can be spooled onto reel70, system 20 can be easily transported to remote locations. Controlline 60 can then be unspooled and ran into a well bore through the useof conventional coiled tubing equipment, including the use ofconventional control vehicles having facilities and equipment foroperating and monitoring system 20. Moreover, control line 60 havingouter jacket 49 provides for better well control capability during theoperation since conventional strippers and blowout preventers can sealoff tubular-shaped lines.

[0034] Liquid liner component transmission lines 31, 41, 51 may have anyinner diameter and outer diameter desired or necessary to effectivelytransmit, or deliver, liquid liner components 35, 45, 55 to applicationsite 95. Preferably, liquid liner component transmission lines 31, 41,51 have small inner and outer diameters, i.e., less than 0.75 inch andless than 1.0 inch, respectively. Therefore, liquid liner componenttransmission lines 31, 41, 51 can be easily twisted, or coiled, togetherand ran in and out of a well bore as a single control line 60.

[0035] Still referring to FIGS. 1-3, liquid liner component transmissionlines 31, 41, 51 are in communication with applicator 90. Applicator 90may include mixing cup 91 and spray head 92. Mixing cup 91 may includean agitator (not shown) or other mixing apparatus to facilitate mixingliquid liner components 35, 45, 55 to form multi-component liquid linercomposition 93.

[0036] Spray head 92 may be any device known to persons skilled in theart that facilitates the dispersion of the multi-component liquid linercomposition 93 onto inner surface 82 of conduit 80 to sufficiently coatinner surface 82. Spray head 92 may include one or more ports 94 throughwhich multi-component liquid liner composition 93 is expelled, e.g.,sprayed, extruded, centrifugally dispersed, from applicator 90. Eachport 94 may provide directional spraying, i.e., one direction, or radialspraying, i.e., multiple directions. Preferably, each port 94 providesradial spraying.

[0037] Additionally, applicator 90 may include a centralizer 99 toassist in maintaining a uniform coverage of multi-component liquid linercomposition 93 being applied to inner surface 82 of conduit 80 byhelping to maintain spray head 92 in the center of conduit 80. It is tobe understood that centralizer 99 may be an integral part of applicator90; may be an additional device attached to applicator 90; may bedisposed above or below spray head 92; and may be separate from sprayhead 92, e.g., attached to control line 60.

[0038] Applicator 90 may be any mechanical, electrical, pneumatic, orhydraulic device known to persons ordinarily skilled in the art thatpermits a liquid to be applied to a surface without contacting thesurface. In the embodiments in which the applicator is electrical,pneumatic, or hydraulic, control line 60 includes a power source line 48in communication with applicator 90 and a power source 47 (FIG. 1). Forexample, electric applicators require an electrical cable as powersource line 48 in communication with the applicator 90 and an electricgenerator (power source 47). Likewise, pneumatic and hydraulicapplicators 90 require a pneumatic line and a hydraulic fluid line,respectively, as power source line 48 in communication with theapplicator 90 and a pneumatic compressor and a hydraulic fluidtank/hydraulic pump, respectively, as power source 47. Power source line48 is preferably a pneumatic line and power source 47 is preferably apneumatic compressor.

[0039] Additionally, power source line 48 is preferably coiled, ortwisted, with liquid liner component transmission lines 31, 41, 51 toform control line 60, and thus, is protected by outer jacket 49. Asshown in FIG. 3, control line 60 includes three spirally twisted liquidliner component transmission lines 31, 41, 51 and power source line 48.

[0040] It is noted that a second power source line 48 may be desired ornecessary to facilitate operation of applicator 90. For example, in theembodiment in which power source line 48 is a hydraulic line, a secondpower source line, also a hydraulic line, in communication with powersource 47 is necessary for proper function of a hydraulic applicator 90.

[0041] In a preferred embodiment, liquid liner component transmissionlines 31, 41, 51 are in communication with a multi-port chemical, orfluid, metering pump 65. Multi-port pump 65 facilitates the delivery ofliquid liner components 35, 45, 55 from reservoirs 30, 40, 50, throughliquid liner component transmission lines 31, 41, 51 to applicator 90.While it is contemplated that any multi-port pump 65 may be included insystem 20, multi-port pump 65 should keep at least two of the liquidliner components separate to facilitate proper delivery, ortransmission, of the liquid liner components to applicator 90 withoutthe multi-component liquid liner composition 93 curing prematurely.Further, multi-port pump 65 preferably pumps pre-determined amounts ofat least two liquid liner components up to about 3,000 psi to about5,000 psi.

[0042] The invention is also directed to methods of applying amulti-component liquid liner composition to the inner surface of aconduit through the use of multiple, individual small diameter liquidliner component transmission lines. The methods may be used to restorethe integrity of old corroded or eroded conduits providing longeroperational life and avoiding costly removal and replacement. Themethods of the invention may also be used to protect new, alreadyinstalled conduits from corrosion or erosion due to liquids or solidstransported through them.

[0043] Conduits of various lengths can be internally coated, or treated,for a wide range of applications, including oil and gas productiontubing, i.e., well bore tubing, petroleum products pipelines, waterlines, sewer lines, and other city utilities, whether the conduit isdisposed horizontally, vertically, or diagonally. In a surprisinglyadvantageous application, the conduit is a vertically (FIG. 2) ordiagonally disposed production tubular having an outer surface 81 and aninner surface 82. Inner surface 82 may be coated with a multi-componentliquid liner composition 93 in accordance with the methods of theinvention at application sites 95 located at distances greater than 200feet from the opening 83 of the conduit 80. As shown in FIGS. 1-2,conduit 80 is a production tubular vertically disposed in ground 100.

[0044] The methods of the invention permit a continuous or intermittentflow of liquid liner components 35, 45, 55 to be pumped down liquidliner component transmission lines 31, 41, 51 and sprayed, extruded, orcentrifugally applied in a radial pattern onto inner surface 82 ofconduit 80. Multi-component liquid liner composition 93 may be appliedover the entire length of inner surface 82 of conduit 80 or in selected,or predetermined, areas, e.g., application site 95. Additionally,applicator 90 may be moved along inner surface 82 of conduit 80 in thedirection of arrows 96, 97 (FIG. 2) to apply multi-component liquidliner composition 93 to larger areas of inner surface 82.

[0045] Intermittent coating of inner surface 82 of conduit 80 withmulti-component liquid liner composition 93 may be controlled byengaging and disengaging multi-port pump 65 which is used to transmitliquid liner components 35, 45, 55 to applicator 90. Multi-port pump 65is preferably a positive displacement pump that provides an individuallycontrolled or metered amount of each liquid liner component 35, 45, 55being transmitted through liquid liner component transmission lines 31,41, 51. In a preferred embodiment, liquid liner components 35, 45, 55are mixed in mixing cup 91 located at, or within (FIG. 2) applicator 90and applied to inner surface 82 of conduit 80 using spray head 92.

[0046] The method of applying multi-component liquid liner compositionsmay be interrupted or spray patterns changed by disengaging multi-portpump 65 and by using surface or downhole valves in control line 60, orin liquid liner component transmission lines 31, 41, 51, operated byelectric, hydraulic, pneumatic, or mechanical actuators. The rate atwhich multi-component liquid liner composition 93 is applied andthickness at which multi-component liquid liner composition 63 isapplied can be adjusted without having to remove control line 60, and/orliquid liner transmission lines 31, 41, 51, and spray head 92 fromconduit 80 to make manual adjustments. Intermittent coating can also beused to avoid coating areas along inner surface 82 that may be adverselyaffected by multi-component liquid liner composition 93, such as gaslift valves and nipple profiles.

[0047] As mentioned above, electrical solenoid actuators for downholecontrol valves would require the use of a power source line 48, e.g., anelectric cable, that can be twisted together with the liquid linercomponent transmission lines 31, 41, 51 (FIG. 3). If desirable, and costeffective, the electrical cable may also be used to operate downholetools and record information such as location of conduit couplings,temperature in conduit 80, multi-component liquid liner composition 93coating thickness, depth and pressure measurements, and other data.

[0048] In one embodiment of the invention, the method of applying amulti-component liquid liner composition 93 to inner surface 82 ofconduit 80 includes the steps of transmitting first liquid linercomponent 35 to application site 95 disposed on inner surface 82 ofconduit 80. Second liquid liner component 45 is then transmitted toapplication site 95 and mixed with first liquid liner component 35 atapplication site 95 to form a multi-component liquid liner composition93. Multi-component liquid liner composition 93 is applied to innersurface 82 of conduit 80 at application site 95, thereby coating innersurface 82 of conduit 80.

[0049] It is to be understood that the phrase “at application site” isto be broadly construed to include any position located within conduit80 near or in close proximity to the application site 95. As shown inFIG. 2, application site 95 is identified as being the area aroundapplicator 90.

[0050] As discussed above, multi-component liquid liner composition 93may be applied to inner surface 82 using applicator 90. Applicator 90may spray, extrude, or centrifugally apply multi-component liquid linercomposition 93 to inner surface 82. Additionally, applicator 90 mayinclude a spray head 92 that provides directional spraying, i.e., themulti-component liquid liner composition 93 is applied in only onedirection from one port 94 located on spray head 92 (although spray head92 may include multiple ports 94, wherein each port 94 is oriented tospray in a different, fixed, direction), or radially spraying, i.e, themulti-component liquid liner composition 93 is applied in multipledirections from each of one or more ports 94 located on spray head 92.

[0051] Liquid liner components 35, 45 may be transmitted to applicationsite 95 through liquid liner component transmission lines 31 and 41respectively. Moreover, liquid liner components 35, 45 may betransmitted to application site 95 by pumping liquid liner components35, 45 from reservoirs 30 and 40 respectively, and through liquid linercomponent transmission lines 31 and 41 respectively.

[0052] Additional liquid liner components, e.g., 55 discussed above, mayalso be transmitted to application site 95 and mixed with the otherliquid liner components, i.e., 35, 45, to form multi-component liquidliner composition 93 that is applied to inner surface 82 of conduit 80at application site 95.

[0053] In another specific embodiment, the method of applying amulti-component liquid liner composition 93 to inner surface 82 ofconduit 80 includes the steps of transmitting first liquid linercomponent 35 to application site 95 disposed on inner surface 82 ofconduit 80 and applying first liquid liner component 35 to inner surface82 of conduit 80 at application site 95. Second liquid liner component.45 is then transmitted to application site 95 and applied to innersurface 82 of conduit 80 at application site 95, thereby formingmulti-component liquid liner composition 93 disposed on inner surface 82of conduit 80 at application site 95.

[0054] Additional liquid liner components, e.g., 55 discussed above, mayalso be transmitted to application site 95 and applied to inner surface82 of conduit 80 at application site 95 to form multi-component liquidliner composition 93 at application site 95.

[0055] While one of the specific embodiments discussed above includesthree reservoirs and three liquid liner component transmission lines, itis to be understood that the system may include any number of reservoirsand liquid liner component transmission lines as desired or necessary tofacilitate the application of a multi-component liquid liner compositionto the inner surface of a conduit. For example, a specificmulti-component liquid liner composition that is desired by the operatorof the system because of conditions, e.g., temperature, humidity,pressure, etc., at the application site may include as few as twodifferent liquid liner components, or as many as four or more differentliquid liner components. In these embodiments, a number of reservoirsand liquid liner component transmission lines will be determined by theoperator based upon the specific liquid liner components selected by theoperator. For example, if four liquid liner components are selected, andall four of the liquid liner components must be kept separated for aslong as possible before being combined to form the multi-componentliquid liner composition and applied to the inner surface of theconduit, then four reservoirs and four liquid liner componenttransmission lines are necessary.

[0056] Alternatively, if only three of the four liquid liner componentsmust be kept separate, i.e., two of the four liquid liner components maybe mixed or combined in one reservoir prior to transmitting them to theapplication site on the inner surface of the conduit, then only threereservoirs and three liquid liner component transmission lines arenecessary. The ability to select the number of reservoirs and liquidliner component transmission lines is within the knowledge of a personordinarily skilled in the art of formulating multi-component liquidcomposition liners.

[0057] Additionally, any of the liquid liner components may be identicalto one another provided at least two of the liquid liner components aredifferent, and the two different liquid liner components are stored inseparate reservoirs and transmitted to the application site throughseparate liquid liner component transmission lines.

[0058] It is to be understood that the invention is not limited to theexact details of construction, operation, exact materials, orembodiments shown and described, as obvious modifications andequivalents will be apparent to one skilled in the art. Accordingly, theinvention is therefore to be limited only by the scope of the appendedclaims.

1-11. (Cancelled):
 12. A method of applying a multi-component liquidliner composition to an inner surface of a conduit, comprising the stepsof: providing a conduit having an inner surface; transmitting a firstliquid liner component to an application site disposed on the innersurface of the conduit; transmitting a second liquid liner component tothe application site, the second liquid liner component being differentfrom the first liquid liner component; mixing the first liquid linercomponent with the second liquid liner component at the application siteto form a multi-component liquid liner composition; and applying themulti-component liquid liner composition to the inner surface of theconduit at the application site.
 13. The method of claim 12, wherein athird liquid component liner component is transmitted to the applicationsite and mixed with the first and second liquid liner components to formthe multi-component liquid liner composition applied to the innersurface of the conduit at the application site.
 14. The method of claim12, wherein the multi-component liquid liner composition includes atleast two additional liquid liner components that are transmitted to theapplication site and mixed with the first and second liquid linercomponents to form the multi-component liquid liner composition appliedto the inner surface of the conduit at the application site.
 15. Themethod of claim 12, wherein the conduit is a production tubular and theapplication site is disposed at least 200 feet below ground.
 16. Themethod of claim 12, wherein the multi-component liquid liner compositionis applied to the inner surface of the conduit by centrifugal spraying.17-20. (Cancelled):